1. Field of the Invention
The present invention relates to devices, such as crampons, adapted to be worn over footwear to provide improved traction.
2. Description of Related Art
There are a variety of devices available today for attachment to footwear to improve traction. It is very common for hikers in snowy or icy environments to employ crampons that attach to bottom of their stiff-soled hiking boots. These heavy-duty devices typically provide series of 1 to 2 inch long spikes across the forefoot and heel of the boot. The spikes are adapted to penetrate ice, snow, and/or loose dirt to provide improved sure-footed hiking or climbing.
A typical crampon is constructed with 8 to 12 spikes attached around the footbed of a relatively inflexible frame. The spikes may be oriented downward and at various outward-facing angles to address traction needs in climbing or descending extreme terrain. Since these devices are adapted to be attached to hiking boots that have soles that may readily flex only 5 to 10 degrees from normal plane, a conventional crampon is constructed from a coherent material, such an inflexible polymer or metal, that can be easily flexed by hand only about 0 to 5–7 degrees off its normal plane. In fact, for extreme climbing conditions, it is desirable to provide a crampon that provides virtually no flexibility so that proper foothold can be maintained under intense pressure.
While conventional crampons work well for their intended hiking and climbing applications, they have numerous deficiencies. First, due to their inflexible nature, most crampons must be worn with boots having very stiff soles. This makes use with common shoes (such as street shoes and boots, running and other athletic shoes, flexible soled hiking boots and shoes, or flexible soled winter boots) quite uncomfortable since the wearer will not be adequately protected from the uneven nature of the crampon bed. Second, the strapping systems for conventional crampons are normally adapted only to attach to large stiff boots. These straps generally do not easily attach to smaller and more flexible common shoes. In fact, since a typical street shoe is quite flexible, flexing readily 45 degrees or more off normal plane, such shoes may slide out of a conventional crampon strapping system.
In order to provide improved traction for more conventional footwear, a number of other solutions have been suggested. A number of manufacturers sell crampon-like devices that are adapted to be attached to only the front (that is, forefoot region) of a shoe or boot. One such device is sold under the trademark SNOWTRACKER by Atlas Co., of San Francisco, Calif. Another commercially available system comprises a two-part device that has a first portion that attaches to the forefoot region on a shoe and a separate second portion that attaches to the heel region of the shoe. While these device do provide improved traction on snow and ice, they are believed to be lacking in attachment ease and security. For example, none of these devices provides a sufficiently secure attachment to withstand the rigors of running.
There are several commercial devices that comprise one or more rubber straps with metal nubs that attach over shoes for improved traction. One such device is sold under the trademark YAKTRAX by Yaktrax Inc. of Washington. These devices are deficient in that they are often shoe size-specific and typically provide only marginally improved traction. Additionally, these devices have a tendency to slip out of position when worn, particularly when encountering stress and strain. Finally, these devices are not designed or constructed for extended wear and intense use that might be required for extended walking, hiking, or running.
A number of patents have been issued related to crampons and similar traction devices. U.S. Pat. No. 4,344,238 describes a traction device that is adaptable to a variety of footwear, but has a strap system that is believed to be inadequate for vigorous activity. Other traction systems are described in U.S. Pat. Nos. 3,795,993, 4,910,883, 5,359,789, and 5,787,612. None of these previous systems is believed to be entirely suitable in one or more of the following design criteria: compaction for storage; light weight; secure attachment and flexibility for active walking and running activities; and/or ready adjustability for use on a wide variety of footwear.